Oil, grease, and hydrocarbon resistant material



Patented July 4, 1939 UNITED STATES PATENT OFFICE OIL, GREASE,

AND HYDROCARBON RESIST- ANT MATERIAL tion of Delaware No Drawing.

Application November 21, 1936,

Serial No. 112,014 2 Claims. (01. 91-68) This invention relates to oil, grease and hydrocarbon resistant material, particularly to oil, grease and hydrocarbon resistant fibrous materials, and more particularly to fibrous materials carrying as a coating a flexible film, which is impervious to oils, greases and hydrocarbons, such as gasoline and the like.

The use of disposable non-refillable containers for lubricating oils and particularly motor oils has become quite common in recent years. The majority of such containers are made of tinned sheet metal, but these containers are relatively expensive, diflicult to seal because of the tendency of the oil to creep on the metal surface and difficult to dispose of conveniently. Moreover, when such containers are emptied, a considerable portion of the oil remains within them due to its high attraction for the metal surface, entailing waste.

It has recently been proposed to use fibrous containers such as containers made from paper, pulp, or the like, in place of the metal containers heretofore used. Such containers are relatively inexpensive being made from cheap materials, such as pressed waste newspaper pulp, and are easily disposed of after use. Such containers are,

of course, normally highly pervious to hydro'car.-.

bons, such as motor oil, and therefore, to be usable, must be provided with a flexible, inexpensive lining which is permanently impervious to oil. Certain coating compositions have been proposed for use in this connection, but so far as known, none of them is entirely successful.

The principal object of this invention is the production of an interiorly coated fibrous container which is highly suitable for merchandising of oils, greases and hydrocarbons.

Another object of this invention is to make an oil, grease and hydrocarbon resistant material with inexpensive fibrous materials as the base, and to provide therefor an inexpensive oil, grease and hydrocarbon impervious fiexible lining.

Another object of this invention is to accom- 5 plish the foregoing objects by a simple and eco-' Thus, if it is desired to make ished container by spinning or blowing into molds of desired shape. Such molds may be formed from wire screen or other foraminous or porous material, as is well understood in the art of fabricating paper pulp. A suitable container may be made from preformed cardboard or paperboard if desired. Thus, sheet paper, cardboard, paperboard, pulpboard, cloth, asbestos board, asbestos paper, or the like, may be subjected to the treatment below described and supplied to the trade for use wherever oil, grease and hydrocarbon resistant fibrous material is desired, or for the subsequent fabrication of containers therefrom by the usual methods known in the paper manufacture art, such as folding, cutting, and adhering with an oil, grease and hydrocarbon resistant adhesive which has an adhesive attraction for the treated surfaces of the product. Within the purview of the invention, there may be used the untreated, uncoated materials above enumerated or such materials which have been treated or coated with other substances than those shown below, as, for instance, rubber-impregnated or rubber-coated paper or cloth, which, of course, is subject to extremely high deterioration when left in contact with oils, greases and hydrocarbons.

By the term hydrocarbon? as used in this specification and claims, it is intended to include all organic compounds containing as elements only carbon and hydrogen, including all saturated aliphatic hydrocarbons, such as gasoline, petroleum naphtha, benzine, ligroin, kerosene, spindle oil, petroleum oil, such as lubricating and motor oil, mineral oil such as Nujol, petrolatum and medicinal salves made with petrolatum as their base, lubricants containing any of the petroleum oils such as soap-thickened mineral oil grease, more commonly known as cup grease, parafiin wax, etc., the aromatic hydrocarbons such as benzene, toluene, xylene, naphthalene, anthracene, etc., the unsaturated aliphatic hydrocarbons, such as ethylene and its homologues, such as amylene, alicyclic hydrocarbons such as cyclohexane, terpene hydrocarbons such as turpentine, etc. While the invention relates primarily to liquid and semi-solid hydrocarbons, yet it is applicable to solid and even gaseous hydrocarbons. Thus, material treated by the process herein disclosed might be used for the retention of gaseous hydrocarbons such as in gasholders, gas tanks, etc.

By the term oil and grease-resistant as used in this specification and claims, there is contemplated resistance to oily and greasy hydrocarbons included in the above enumeration, as well as resistance to vegetable and animal oils such as peanut butter, mayonnaise, linseed oil, hydrogenated cottonseed oil and to the higher fatty acids such as stearic acid, oleic acid, etc. In general, by the term oil, grease and hydrocarbon-resistant there is contemplated resisance to any oily or greasy or hydrocarbon material.

It has been discovered that by the application to the fibrous base material to be rendered oil, grease and hydrocarbon-resistant of a plurality of coatings, at least one of which is a cellulose derivative and at least one of which is a watermiscible organic binder such as glue or watersoluble gums fiexibilized by polyhydric alcohols, that the resulting material is highly impervious to hydrocarbons, oils and greases, and retains this impervlousness indefinitely. There may be used only the two coatings referred to or other coatings in addition.

To form the cellulose derivative coating, there is employed as coating material the usual lacquer made up of the cellulose derivative, suitable solvents therefor, and suitable plasticizers and softeners, but it is preferred to use an aqueous emulsion of a cellulose derivative or of a cellulose derivative lacquer. As cellulose derivative, cellulose nitrate, cellulose acetate, ethyl cellulose, etc., may be used, but cellulose nitrate is preferred. A suitable formula for the emulsion which is preferred is given in the examples below, but it is to be understood that other formulae and proportions may be used and that any coating of a cellulose derivative is deemed to fall within the spirit of this invention. The coating is produced by any appropriate coating process. Thus, in the case of a pressed pulp container, cellulose derivative solution or emulsion may be poured into the interior and the container rotated while emptying it, allowing it to drain drip-free and drying thoroughly, preferably under forced draft conditions, and at elevated temperature.

As the water-miscible organic binder, there may be used any of the protein glues such as albumen, casein, gelatin, animal glue, hide glue or bone glue, although animal, hide or bone glue are preferred, or there may be used any of the water-soluble gums such as gum karaya, gum tragacanth, gum acacia (gum arabic), dextrine (British gum), etc. To render this film flexible, there is incorporated in the initial coating composition one or more polyhydric alcohols, such as ethylene glycol, diethylene glycol, glycerol, xylitol, iditol or sorbitol, or mixtures of any of these polyhydric alcohols. In general, films fiexibilized with the dihydric alcohols are less resistant to hydrocarbons than those fiexibilized with the higher polyhydric alcohols. However, by using such films in conjunction with heavy well-dried cellulose derivative coats, the resulting articles are sufficiently resistant to oils, greases and hydrocarbons for most purposes. The use of glycerol and higher polyhydric alcohols than the dihydric alcohols is more advantageous in that films fiexibilized with such higher polyhydric alcohols may be used with lighter and/or less thoroughly dried cellulose derivative coats. Films fiexibilized with glycerol are very impervious to oil, yet it is preferred to use films fiexibilized with sorbitol since sorbitol is not soluble to the slightest degree in hydro-carbons such as gasoline or lubricating oils while glycerol exhibits a slight solubility in those hydrocarbons, and since films of glue flexibilized with sorbitol are unexpectedly resistant to the action of oils, greases and hydrocarbons, and retain this impermeability even after a great many months of storage in contact with them, whereas films of glue fiexibilized with glycerol show signs of weakening after several months of storage under the same conditions. Glycerol therefore may be used as the fiexibilizing agent when the time of storage in contact with hydrocarbons is relatively short and sorbitol may be used when the time of storage is not known absolutely and may therefore be extremely long or when it is known that it will be extremely long.

Sorbitol does not impart as great flexibility to the films as does glycerol or the dihydric alcohols enumerated above. Therefore, for great flexibility and maximum oil, grease and hydrocarbon resistance, it is preferred to use mixtures of sorbitol with glycerol or a dihydric alcohol, or mixtures of the same. The proportions of sorbitol and the other polyhydric alcohols used in this mixed fiexibilizer are infinitely variable in accordance with the properties desired or required in the product, as will be apparent to those skilled in the art.

Mannitol and dulcitol, when used alone as the fiexibilizer, tend to crystallize from the film causing the film to lose its impermeability, although these hexahydric alcohols are insoluble in oils, grease and hydrocarbons. It is desirable when using these hexahydric alcohols to add some of a lower polyhydric alcohol such as glycerine or the glycols to inhibit the crystallization.

The proportions of fiexibilizer and watermiscible organic binder in the coating composition are variable over wide range. However, it is preferred to use a ratio of one to two parts of fiexibilizer to one part of the'binder. The fiexibilized coating may be applied by any known coating process. Thus, it may be applied to preformed containers in the same manner as above described for the cellulose derivative coating, but it is preferable to heat it before coating with it.

Oil, grease and hydrocarbon resistance is obtained in the product whether there is first applied the cellulose derivative coating, followed by the fiexibilized water-miscible organic coating, or whether the coatings are applied in the reverse order with the fiexibilized water-miscible organic coating next to the base material and superimposed thereupon the cellulose derivative coating. However, the first mentioned order is preferred, especially when using an aqueous cellulose derivative lacquer emulsion on a fibrous base since the water of the emulsion is taken up by the porous base material very rapidly, resulting in a high adherence of the lacquer, and a very much shortened drying time is necessary before the fiexibilized coating is applied. Moreover, containers so prepared in which the oil-repellant coat is in direct contact with the hydrocarbon ,oil drain more completely on emptying. The

fiexibilized water-mscible organic binder coat shows such a high adherence to the cellulose derivative undercoat that the two coats cannot be separated. The cellulose derivative undercoat protects the water-miscible organic film from atmospheric moisture or dryness which might penetrate through the fiber base, while the watermiscible organic coating protects the cellulose derivative undercoat from contact with the oil, grease or hydrocarbon material which might tend to dissolve the plasticizer therefrom, resulting in leakage. Thus, it is seen that the disssimilar coats described cooperate in a new and novel manner and produce results which would not be obtainable with two cellulose derivative coats or two water-miscible organic coats. Moreover, a more economical coating is obtained using the coatings described. However, with water-miscible organic binder as the first coat, and cellulose derivative as the second'coat, many of the advantages of the invention are attained and the container will not fail altogether in humid climates.

When reference is made to sorbitol, there is also contemplated a technical grade of sorbitol syrup prepared by the catalytic hydrogenation or electrolytic reduction of glucose and which may contain as impurities some unreduced glucose, ash and salts of organic acids.

In the following examples, there are set forth several preferred embodiments of the invention. It is to be understood, however, that the invention is not limited thereto.

EXAMPLE 1 Coating A (cellulose derivative) Water phase, 28 by weight Per cent by weight Water 99 Sulfonated castor oil (75% grade)- 1} gallon Grams per gal.

Sodium salt of sulfonated lauryl alcohol extracted with methyl alcohol (DuponolMe) 19 Methyl cellulose (Tylose S-25) 11.4

Lacquer phase, 71 /2% by weight Liquids, 1 gallon.

Per cent by volume Octyl acetate 5 Butyl acetate 30 Butyl alcohol Toluol 21 Blown castor oil 34 Solids.

Nitrocellulose (7 sec.) oz 25 The water phase is prepared by dissolving the sulfonated castor oil in the distilled water, then adding to one gallon of the resulting solution the sodium salt of sulfonated lauryl alcohol and the methyl cellulose in the proportion stated. The lacquer phase is made by dissolving the nitrocellulose in the previously prepared mixture of solvents and plasticizer. The given proportion of lacquer phase is then emulsified in the water phase by passing the mixture through a colloid mill or homogenizer.

Coating B (glue) Sorbitol per cent by weight Hide glue (having a gel strength of 400- 415 g.) per cent by weight 15 Water per cent..- '70 The sorbitol and water are heated in a jacketed kettle with agitation to 170 F. The glue is then added and heating is continued between 170 and 180 F. until a uniform grain-free mixture is obtained. The water removed by evaporation is replaced. Preferably 1% of B-naphthol on the weight of the glue or similar anti-molding compound is added.

A container of pressed paper pulp sized throughout during manufacture with 10% of paraflin wax is first coated with coating A by filling the container with the lacquer emulsion and immediately pouring it out with a rotatory motion. The excess is allowed to drain dripfree and the container is then dried for 15 minutes at, 150-160 F. or for 2 hours at l-130 F. in a drying chamber equipped with a fan for circulating the air. The container is then removed and coated with coating B which is applied at a temperature of 160-180 F., the manner of application being otherwise identical with that of coating A. The container is then dried for 16 hours at room temperature and then for two hours at 150- 160 F. in the same type of drying chamber as that described above.

EXAMPLE 2 Coating A The same as in Example 1.

Coating B (glue) Per cent by weight Glycerol 16% Hide glue (gel strength 400-415 g.) 16% Water 66% This mixture is prepared in the same manner as coating B of Example 1.

A pressed paper pulp container such as used in Example 1 is coated with the above coatings exactly as in Example 1 except that coating A is .dried for two hours at 120 -130 F. before application of coating B.

'ExAMrLr: 3

Coating A The same as in Example 1.

Coating B (glue) This mixture is prepared in the same manner as coating B of Example 1.

The coatings are applied to the pressed paper pulp container of Example 1, exactly as in that example.

. EXAMPLE 4 Coating A The same as in Example 1.

Coating B The same as in Example 1.

The container of Example 1 is coated first with coating B in the manner previously described, and then dried for sixteen hours at room temperature. Coating A is then applied in the manner described in Example 1 for coating A. This coat is then dried for two hours at 120-130 F.

The containers produced as described in Examples 1 to 4 are highly impervious to hydrocarbons and are especially adapted for use as non-refillable containers for dispensing motor and lubricating oils. The use of pressed paper pulp for such containers is extremely advantageous since it is cheap and seamless. While reference has been made to containers made from such pulp sized with wax, it will be obvious that containers made from unsized pulp or from pulp sized with other agents, such as 5% of rosin size, may be used.

Coating A is first uniformly applied by spraying on 16 oz. cotton duck. The coated fabric is dried at 160 F. forthirty minutes. Then coating B at a temperature of ISO- F. is sprayed uniformly as a second coat, and dried at 150-160 F. for two hours. The fabric thus prepared is extremely resistant to penetration by hydrocarbons and, for example, may be used in the fabrication of hose or tubing through which gasoline or other hydrocarbons are to be passed.

EXAMPLE 6 Coating A The same as in Example 1.

Coating B The same as in Example 1..

Asbestos paper is sprayed with coatings A and B exactly as in Example 5 except that the time of drying of coating A at 150-160" F. is reduced to fifteen minutes. The product is extremely oilresistant, and may be used as gasket material where oil resistance is a prime requisite, provided the temperature to which it is subjected does not exceed 150 F.

, EXAMPLE 7 Coating A (cellulose derivative) The same as in Example 1.

Coating B (glue) Per cent by weigzhst Mannitol Glycerine 7.5 Hide glue 15.0 Water 70.0

The mannitol and water are heated in a jacketed kettle to F. The glue is then added and heating is continued between 170 and F. until a uniform grain-free mixture is obtained. The water removed by evaporation is replaced.

Coatings A and B are applied to a pressed paper 7 pulp container exactly as in Example 1.

EXAMPLE 8 Coating A (cellulose derivative) The same as in Example 1.

Coatin B (glue) Per cent by weigh Dulcitol 7:5 Glycerine '7 .5 Hide glue 15.0

These ingredients are commingled in exactly the same manner as in Example 7.

The coatings A and B are applied to a pressed paper pulp container exactly as in Example 1.

EXAMPLE 9 Coating A (cellulose derivative) The same as in Example 1.

Coating B(de:ctrine) Per cent by weight Corn dextrine 28 Sorhi tnl 28 Water 44 EXAMPLE 10 Coating A (cellulose derivative) The same as in Example 1.

Coating B (dextrine) Per cent by weight Corn dextrine 28 Glycerine 14 Sorbitol 14 Water 44 These ingredients are commingled in the same manner as in Example 9.

The coatings are applied in the same manner as in Example 9. The resulting containers were quite impervious to gasoline and motor oil.

As will be apparent to those skilled in the art, if oil, grease or hydrocarbon resistance is desired in a portion only of a container or surface, only that portion is treated by the process herein dis closed.

It is also to be understood that it is not desired to be limited to the above description and specific examples. Thus,.any lacquer or lacquer emulsion comprising a cellulose derivative may be used. Any cellulose ester or ether may be used. Other plasticizers and solvents than those shown may be used. Compatible resins either natural or synthetic may be added to the cellulose derivative coating composition. The coats may be applied in any manner and the invention is not to be limited to the specific methods shown. The proportion of ingredients, order of mixing, and temperatures of application, may all be varied considerably without departing from the spirit of the invention. Thus, if desired, instead of the drying procedure described for coating B in the examples, the coating of the superimposed glue may be dried at atmospheric temperature for a period of from 15 minutes to twenty-four hours, preferably for 16 hours, before being placed in the oven, in order to allow the melting point of the glue mixture to rise above that of the drying oven by evaporation of. water, or formaldehyde or paraformaldehyde may be added in the glue mix so as to set the glue coating before drying, or the glue-coating may be sprayed with aqueous formaldehyde after its application and prior to drying. When formaldehyde is used in glue coat,

it is highly preferred to use .14-.16% of 100% formaldehyde (CI-I20) calculated on the weight of the glue. If desired, drying of the glue coat at elevated temperatures may be altogether eliminated by the use of the specified proportion of formaldehyde and by the expedient of drying at room temperature for 16 hours. Other drying temperatures than those specified in the examples may be used if desired. Ethylene glycol or diethylene glycol may be used in conjunction with sorbitol for softening the water-miscible organic binder coat. In general, any polyhydric alcohol which is substantially insoluble in hydrocarbons may be used, but those which exhibit hygroscopic properties are preferred. Any of the coatings described in the above examples may be used interchangeably.

By oil, grease and hydrocarbon-resistant as used in the claims is meant impermeable to and not decomposed by or chemically affected by the oils, greases and hydrocarbons generally, including those herein enumerated. It is not intended to be limited to such hydrocarbons as gasoline and motor oil to which the invention is particularly applicable. By water-miscible organic binder as used in the claims, there is-meant water-miscible organic binders of the type herein disclosed and similar materials, namely protein glues such as hide or bone glue or casein, or the water-soluble gums such as gum arabic, gum acacia, gum karaya, gum tragacanth, dextrine, etc, By glue there is meant protein glues including hide and bone glue, gelatine, casein, albumin, zein, etc. By water-soluble gums" is meant such natural gums as those just enumerated, dextrine, and similar gums which are termed jwater-soluble by those skilled in the arts. The terms a cellulose derivative, a water-miscible organic binder, a water-soluble gum and a polyhydric alcohol are intended to cover single or mixed ingredients falling within these expressions.

In co-pending application, Serial Number 116,825 filed Dec. 19, 1936, there is disclosed the use of a water-miscible organic binder coatsistant. In co-pending application, Serial Number 111,599, filed Nov, 19, 1936, there is disclosed a coatingcomprising a water-miscible organic binder flexibilized with sorbitol or mixtures of sorbitol and lower polyhydric alcohols.

Having described our invention, what we claim is:

1. An oil, grease and hydrocarbon-resistant fibrous material comprising a fibrous base provided with two superimposed flexible coatings, the first coating which is in contact with the fibrous base being highly resistant to moisture and consisting essentially of a plasticized cellulose derivative, and the second coating which is superimposed over said first coating and which is to be exposed to oil, grease or hydrocarbon :being highly resistant to oils, greases and hydrocarbons and consisting essentially of a water-miscible organic binder selected from the group consisting of protein glues and water soluble gums flexibilized with a polyhydric alcohol flexibilizer containing at least 50% of sorbitol.

2. An oil, grease and hydrocarbon-resistant v fibrous material comprising a fibrous base *provided with two superimposed flexible coatings, the first coating which is in contact with the fibrous base being highly resistant to moisture and consisting essentially of a plasticized cellulose derivative, and the second coating which is superimposed over said first coating and which is to be exposed to oil, grease or hydrocarbon. be-

, ing highly resistant to oils,- greases and hydrocarbons and consisting essentially of awatermiscible organic binder selected from the group consisting of protein glues and water soluble gums fiexibilized with a polyhydric alcohol flexbbilizer containing 50% of sorbitol and 50% 01" glycerinc.

- KENNETH R. BROWN.

EDMOND H. BUCY. 

